Electric multiple switches



April 23, 1957 F.TR1NGAL1 2,790,039

- ELECTRIC MULTIPLE SWITCHES Filed D60. 7, 1953 2 Shee'ts-Sheet l Apnl23, 1957 F. TRINGALI ELECTRIC MULTIPLE SWITCHES 2 Sheets-Sheet 2 FiledDec. 7, 1953 ELECTRIC MULTIPLE SWITCHES Francesco Tringali, Augusta,Italy Y Application December 7,1953, Serial No. 396,383

Claims priority, application Italy December 20, 1952 s caaims. (c1. 20o-9) Multiple switchesV normally used in radio apparatus (sliding contactswitches) have some drawbacks due to their mechanical construction,which after a shorter or longer period of operation result in anincreaseof the electric resistance between the contacts, which might cause thetotal interruption of the current, especially if the current, flowingthrough the circuitincluding said contacts, is of a very high frequency(short waves).

Other types of similar switches, the Vdrum switches, though being morereliable in operation, have the drawback of being cumbersome andexpensive, and therefore are hardly or. not at all employable inapparatus Where the space is limited or Where the economic factor isprevailing.

An object of Vthis invention is to eliminate the mentioneddisadvantages, by providing a switch of a type absolutely free fromWrong contacts, having limited dimensions and being economical enough tosubstitute with advantage for the switches with sliding contacts.

This is possible because of a new arrangement and shape of the contactsand of `a characteristic arrangement and shape of the contactors.

In the annexed drawings an embodiment of a multiple commutator inaccordance with this invention is shown by way of example.

Fig. l is a plan View of a stator member included in a switch embodyingthe present invention;

Fig. 2 is a sectional view taken along the line II-II of Fig. l;

Fig. 3 is an electrical diagram showing the Various commutationsobtainable with the switch illustrated in Figs. 1 and 2;

Fig. 4 is a plan View similar to Fig. l,V but showing another embodimentof the invention;

Fig. 5 is a sectional view taken along the line V-V of Fig. 4;

Fig. 6 is an electrical diagram showing the various commutationsobtainable with the switch of Figs. 4 and 5.

Fig. 7 is a plan view of a rotor member to be used inV connection witheither of the stator members illustrated in Figs. l and 4, respectively;

Fig. 8 is a side elevational view of the rotor member of Fig. 7;

Fig. 9 is a sectional view taken along the line lX-IX of Fig. 7;

Fig. l() is a side elevational view of a switch assembly made up'of aplurality of the rotor and stator members illustrated in Figs. l to 9,inclusive;

Fig. 11 is a fragmentary side' elevational view of a modied form ofrotor contactor; and

Fig. l2 is a side elevational view, partly broken awayV and in section,of the rotor contactor of Fig. l1.

Referring to the drawings, Figs. l, 2 and 3 illustrate an embodiment ofthe invention, wherein, a small plate `1 ofinsulating material, havingthe shape of a circularV crown, has lixed thereon, radially extendingmetallic contacts 2 arranged with equal angular distances therebetweenand with their ends 3 shaped in angular form to nited States Patent ttact crowns of the described type which `are spaced apart and, form apair of elements of the stator, and to secure together several of suchpairs for forming the complete stator of the commutator. Y

The two small contact plates of each pair can be made in the form asabove described, so as to realize the commutation according to theelectric diagram of Fig-` ure 3; alternatively, the contacts of one ofthevsmall plates of each element may have another shape, as shown inFigs. 4 and 5, in order to obtain the commutation ac-v cording to theelectric diagram of Figure 6; or otherwise the two crowns forming eachstator element may be made, if this should be practically convenient, bya single crown of insulating material having a suitable thickness, onwhich the two Contact sets are fixed or incorporated Salong the opposedfaces of the crown, with each set of c it forms a couple.

It is evident that the number of the sectors determines the number ofdifferent circuits controllable by the switch, whereas `the number ofthe angular cavities Vof each sector determines the number of thepositions or commutations of the switch.

It is also eviden-t that, by suitably joining several elements (pairs)the number of the commutable ways, as Well as the number of thepositions, can be increased at will, as shown on Figure 10.

Figs. 7, 8 and 9 show a rotor element of the switch, consisting of acylindrical body of insulating material 11 in which there are radialchannels 12, containing cylindrical contacting rollers 13 and pressuresprings 14, which press the corresponding rollers in a radially outwarddirection.

The rotor element 11 is xed by means of suitable members in a concentricposition in respect to the stator element and can turn with its axle 15,on which it is xed, within the crowns of the stator element, as shown onFigure 10.

A rotatory movement imparted to the axle 15, produces the step-by-steprotational movement of the rotor, which is successively stopped in exactcorrespondence to the angular cavities (stopping notches) ofthe severalcon` tacts, owing' to the rollers 13 entering the corresponding notchesunder the pressure of the springs, so progressively establishing at eachsnapping one or more contact bridges (according to the numberY ofcontactors contained in the rotor) between the corresponding contacts ofthe two small plates of each stator pair. Owing to the radially outwardforce continuously exerted by the springs on the contacting roller, andowing also to the particular shape ofthe angular notches of the severalcontacts and to the shape of the contacts, the engagement between theroller 13 and the contacts is always reliable, even after a an,... ...d

long time of use, with an electric contact resistance practicallyneglectable.

Obviously, the number of the contactors of each rotor element isdetermined by the number of the sectors or ways of the Vstator element,and it is possible to couple on the same rotation axle several identicalrotor elements in correspondenceof a same number of stator elements,also identical, in order to increase the number of the ways and of thepositions of the switch according to Figure 10.r i

According to a further form of realization, shown on Figs. 11 and 12,the contactors can have the shape of rectangular metallic bodies 16having al suitable thickness and round outside edges yfor engagementwiththe contacts of the stator 17, and which are held in radial guides 18 onthe rotor and forced in a centrifugal direction against the surroundingcontacts of Vthe rotor by means of springs 19.

yOf course, the shape and the particulars of construction can bemodified in accordance with the practical requirements, withoutdeparting from the scope of the invention.

Iclaim:

1. A multiple switch for the commutation of radio frequency electricalcurrents, said switch compn'sing at least one stator member and acoaxial rotor member associated with each stator member, said statormember including at least two thin annular members of insulatingmaterial in axially Ispaced apart relation to provide an air gaptherebetween, a plurality of blade contacts fixed on each of saidannular members, each of said blade contacts having at least oneradially inward opening V-shaped notch `axially aligned with acorresponding 2. A multiple switch for the commutation of radiofrequency electrical currents as in' claim 1; wherein each statorfurther includes insulating spacing members hold- 'ing said annularrmembers in axially spaced relation.

3. A multiple switch' for the commutation of radio frequency electricalcurrents as in claim 1; wherein each of said blade contacts is a thinelongated conducting member arranged radially and having a shtail-shapedradially inward end dening said V-shaped notch.

References Cited inthe tile of this patent UNITED STATES PATENTS1,853,506 carter Apr. 12, 1932 2,015,399 Grothe Sept. 24, 1935 2,201,881Bryant et al. May 21, 1940 2,418,616 Batcheller Apr. 8, 1947 FOREIGNPATENTS 605,385 France Feb. 16, 1926 804,247 France July 27, 1936571,395 Great Britain Aug. 22, 1945 611,133

Great Britain Oct. 26, 1948

